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Timeline of Earth
This timeline of natural history summarizes significant and events from the to the arrival of modern s. Times are listed in millions of years, or megaanni ( ). Dating of the Geologic record The is the (layers) of in the planet's and the science of is much concerned with the age and origin of all rocks to determine the history and formation of Earth and to understand the forces that have acted upon it. is the timescale used to calculate dates in the planet's geologic history from its origin (currently estimated to have been some 4,600 million years ago) to the present day. measures the steady decay of s in an object to determine its age. It is used to calculate dates for the older part of the planet's geological record. The theory is very complicated but, in essence, the radioactive elements within an object decay to form s of each . Isotopes are s of the element that differ in but share the same general properties. Geologists are most interested in the decay of isotopes (into ) and (into ). Carbon-14 aka works for organic materials that are less than about 50,000 years old. For older periods, the process is more accurate. Radiocarbon dating is carried out by measuring how much of the carbon-14 and nitrogen-14 isotopes are found in a material. The ratio between the two is used to estimate the material's age. Suitable materials include , , , s, s and s. It is assumed that rock exists in layers according to age, with older beds below later ones. This is the basis of . The ages of more recent layers are calculated primarily by the study of fossils, which are remains of ancient life preserved in the rock. These occur consistently and so a theory is feasible. Most of the boundaries in recent geologic time coincide with s (e.g., the s) and with the appearances of new species (e.g., s). The earliest Solar System In the earliest solar system history, the Sun, the s and the were formed. The inner solar system aggregated more slowly than the outer, so the terrestrial planets were not yet formed, including and . *c.4,570 Ma – A explosion (known as the primal supernova) seeds our galactic neighborhood with s that will be incorporated into the Earth, and results in a in a dense region of the galaxy. The , which formed 2 million years before the , are a key signature of a explosion. *c.4,567±3 Ma – Rapid collapse of , forming a third-generation , the , in a region of the (GHZ), about 25,000 light years from the center of the . *c.4,566±2 Ma – A (from which Earth eventually forms) emerges around the young , which is in its stage. *c.4,560–4,550 Ma – Proto-Earth forms at the outer (cooler) edge of the of the . At this stage the of the Sun was only about 73% of its current value, but liquid water may have existed on the surface of the Proto-Earth, probably due to the of high levels of and present in the atmosphere. begins: because the solar neighbourhood is rife with large planetoids and debris, Earth experiences a number of giant impacts that help to increase its overall size. Precambrian Supereon *c.4,533 Ma – The Precambrian (to c.541 Ma), now termed a "supereon" but formerly an , is split into three geological periods called : Hadean, Archaean and Proterozoic. The latter two are sub-divided into several eras as currently defined. In total, the Precambrian comprises some 85% of geological time from the formation of Earth to the time when creatures first developed exoskeletons (i.e., hard outer parts) and thereby left abundant fossil remains. Hadean Eon *c.4,533 Ma – Hadean Eon, Supereon and unofficial start as the - system forms, possibly as a result of a glancing collision between proto-Earth and the hypothetical . (The Earth was considerably smaller than now, before this impact.) This impact vaporized a large amount of the crust, and sent material into orbit around Earth, which lingered as rings, similar to those of Saturn, for a few million years, until they coalesced to become the Moon. The Moon geology period starts. Earth was covered by a tic ocean deep resulting from the impact energy from this and other s during the , and energy released by the forming. Outgassing from crustal rocks gives Earth a atmosphere of , , , , and , with lesser amounts of , , then . With further full outgassing over 1000-1500 K, nitrogen and ammonia become lesser constituents, and comparable amounts of methane, carbon monoxide, carbon dioxide, water vapour, and hydrogen are released. *c.4,500 Ma – Sun enters : a sweeps the Earth-Moon system clear of debris (mainly dust and gas). End of the Early Bombardment Phase. Era begins on Earth. *c.4,450 Ma – 100 million years after the Moon formed, the , formed of lunar , differentiates from lower s. The earliest Earth crust probably forms similarly out of similar material. On Earth the period starts, in which the Earth's crust cools enough to let oceans form. *c.4,404 Ma – First known , found at in . s show presence of a solid and . Latest possible date for a to form, produced by the Earth's crust , reinforced by water and possibly s delivered by impacts and s (including type shown to be high in a number of and s (PAH)). *c.4,300 Ma – Era begins on Earth. *c.4,250 Ma – , based on unusually high amounts of light isotopes of carbon, a common sign of , found in Earth's oldest mineral deposits located in the of . *c.4,100 Ma – Era begins on Earth. of the Moon (and probably of the Earth as well) by s and s, produced possibly by the of into the as a result of s between and . "Remains of " were found in 4.1 billion-year-old rocks in Western Australia. According to one of the researchers, "If life arose relatively quickly on Earth ... then it could be common in the ." *c.4,030 Ma – of , first known , or of minerals. Archean Eon Eoarchean Era *c.4,000 Ma – Archean Eon and Era start. Possible first appearance of plate tectonic activity in the Earth's crust as plate structures may have begun appearing. Possible beginning of Orogeny forces of faulting and folding create first . Origins of life. *c.3,930 Ma – Possible stabilization of begins *c.3,920–3,850 Ma – Final phase of Late Heavy Bombardment *c.3,850 Ma – Greenland shows evidence of 12C enrichment, characteristic of the presence of photosynthetic life. *c.3,850 Ma – Evidence of life: off Western contains evidence of , of a type consistent with . *c.3,800 Ma – Oldest s found. . First complete continental masses or , formed of blocks, appear on Earth. Occurrence of initial felsic igneous activity on eastern edge of Antarctic craton as first great continental mass begins to coalesce. begins to form - first rocks of the and are laid down *c.3,750 Ma – forms *c.3,700 Ma – found to be in 3.7 billion-year-old discovered in Stabilization of begins: old tonaltic gneisses laid down Paleoarchean Era *c.3,600 Ma – Era starts. Possible assembly of the ; oldest cratons on Earth (such as the Canadian Shield, East European Craton and Kaapval) begin growing as a result of crustal disturbances along continents coalescing into Vaalbara - stabilizes. Formation of : uplifts on the eastern edge of , oldest mountains in Africa - area called the "genesis of life" for exceptional preservation of fossils. stabilizes: these gneisses become the "bedrock" for the formation of the in Australia - noted for the survival of the s where the oldest mineral, a zircon was uncovered. *c.3,500 Ma – Lifetime of the : split between bacteria and occurs as "tree of life" begins branching out - varieties of begin to radiate out globally. Fossils resembling , found at , . *c.3,480 Ma – Fossils of found in 3.48 billion-year-old discovered in . First appearance of organisms that grow at between different types of material, mostly on submerged or moist surfaces. *c.3,460 Ma – Fossils of in . stabilizes from the suture of two smaller crustal blocks, the Tokwe Segment to the south and the Rhodesdale Segment or Rhodesdale gneiss to the north. *c.3.400 Ma – Eleven of s are preserved in the of the Pilbara craton in Australia. Because is fine-grained -rich , or microfibrious material, it preserves small fossils quite well. Stabilization of begins. *c.3.340 Ma – Johannesburg Dome forms in South Africa: located in the central part of Kaapvaal Craton and consists of trondhjemitic and tonalitic granitic rocks intruded into mafic-ultramafic greenstone - the oldest granitoid phase recognised so far. *c.3,300 Ma – Onset of . Intrusion of granitic on the Kaapvaal Craton. *c.3,260 Ma – One of the largest recorded s occurs near the , when a 58 km (36 mi) asteroid leaves a crater almost 480 km (300 mi) across – two and a half times larger in diameter than the . Mesoarchean Era *c.3,200 Ma – Era starts. in South Africa form - contain some of the oldest microfossils mostly spheroidal and carbonaceous alga-like bodies. *c.3,200–2,600 Ma – Assembly of the to cover between 12–16% of the current . Formation of . *c.3,100 Ma – : second round of fossilizations including Archaeosphaeroides barbertonensis and . Gneiss and greenstone belts in the Baltic Shield are laid down in , and northeastern Finland. *c.3,000 Ma – Humboldt Orogeny in Antarctica: possible formation of in . Photosynthesizing cyanobacteria evolve; they use water as a reducing agent, thereby producing oxygen as a waste product. The oxygen initially oxidizes dissolved iron in the oceans, creating iron ore - over time oxygen concentration in the atmosphere slowly rises, acting as a poison for many bacteria. As Moon is still very close to Earth and causes tides 1,000 feet (305 m) high , the Earth is continually wracked by hurricane-force winds - these extreme mixing influences are thought to stimulate evolutionary processes. Rise of : microbial mats become successful forming the first building communities on Earth in shallow warm tidal pool zones (to 1.5 Gyr). forms. *c.2,940 Ma – of western Australia forms by the accretion of a multitude of formerly present blocks or terranes of existing continental crust. *c.2,900 Ma – Assembly of the supercontinent, based upon the core of the , formed at c.3100 Ma. Narryer Gneiss Terrane (including Jack Hills) of Western Australia undergoes extensive metamorphism. Neoarchean Era *c.2,800 Ma – Era starts. Breakup of the : Breakup of supercontinent Ur as it becomes a part of the major supercontinent Kenorland. Kaapvaal and Zimbabwe cratons join together. *c.2,770 Ma – Formation of on the southern margin of Pilbara Craton - last stable submarine-fluviatile environment between the Yilgarn and Pilbara prior to rifting, contraction and assembly of the intracratonic . *c.2,750 Ma – Renosterkoppies Greenstone Belt forms on the northern edge of the Kaapvaal Craton. *c.2,736 Ma – Formation of the in , , . *c.2,707 Ma – begins to form in present-day and - first known Precambrian - first phase results in creation of 8 km long, 40 km wide, east-west striking Misema Caldera - coalescence of at least two large mafic es. *c.2,705 Ma – Major eruption, possibly global - possible mantle overturn event. *c.2,704 Ma – Blake River Megacaldera Complex: second phase results in creation of 30 km long, 15 km wide northwest-southeast trending New Senator Caldera - thick massive mafic sequences which has been inferred to be a subaqueous lava lake. *c.2,700 Ma – Biomarkers of discovered, together with s ( s of ), associated with films of eukaryotes, in shales located beneath banded iron formation hematite beds, in Hamersley Range, Western Australia; skewed sulfur isotope ratios found in pyrites show a small rise in oxygen concentration in the atmosphere; forms in Wabigoon greenstone belt — contains well preserved homoclinal chain of greenschist facies, metamorphosed intrusive, volcanic and sedimentary layers (Mattabi pyroclastic flow considered third most voluminous eruptive event); stromatolites of in Zimbabwe form — first verified reef community on Earth. *c.2,696 Ma – Blake River Megacaldera Complex: third phase of activity constructs classic east-northeast striking which contains a 7-to-9-km-thick succession of mafic and felsic rocks erupted during five major series of activity. in present-day Ontario and Quebec begins to form: considered world's largest series of Archean greenstone belts, appears to represent a series of thrusted subterranes. *c.2,690 Ma – Formation of high pressure granulites in the Limpopo Central Region. *c.2,650 Ma – Insell Orogeny: occurrence of a very high grade discrete tectonothermal event (a UHT metamorphic event). *c.2,600 Ma – Oldest known giant carbonate platform. Saturation of oxygen in ocean sediments is reached as oxygen now begins to dramatically appear in Earth's atmosphere. Proterozoic Eon The Proterozoic (from c.2500 Ma to c.541 Ma) saw the first traces of . remains of and . Paleoproterozoic Era Siderian Period *c.2,500 Ma – Proterozoic Eon, Paleoproterozoic Era, and Period start. Oxygen saturation in the oceans is reached: form and saturate ocean floor deposits - without an oxygen sink, Earth's atmosphere . led by cyanobacteria's oxygenic photosynthesis - various forms of Archaea and anoxic bacteria become extinct in first great on Earth. or Kenoran: assembly of out of the Canadian and - formation of and Slave Province. *c.2,440 Ma – Formation of in Australia. *c.2,400 Ma – starts, probably from oxidation of earlier methane greenhouse gas produced by burial of organic sediments of photosynthesizers. First . Formation of in southern India. *c.2,400 Ma – impact structure forms. This is the oldest known impact crater whose remnants are still recognizable. in southern India stabilizes. Rhyacian Period *c.2,300 Ma – period starts. *c.2,250 Ma – forms: world's largest reserves of (platinum, palladium, osmium, iridium, rhodium and ruthenium), as well as vast quantities of iron, tin, chromium, titanium and vanadium appear – formation of begins. *c.2,200–1800 Ma – found, produced by iron in weathered sandstone being exposed to oxygen. , series of tectonic, metamorphic and plutonic events establish to the north of and Man Shield to its south – Birimian domain of West Africa established and structured. *c.2,200 Ma – Iron content of ancient fossil soils shows an oxygen built up to 5–18% of current levels. End of Kenoran Orogeny: invasion of Superior and Slave Provinces by basaltic dikes and sills – Wyoming and Montana arm of Superior Province experiences intrusion of 5 km thick sheet of chromite-bearing gabbroic rock as forms. *c.2,100 Ma – ends. Earliest known fossils found. Earliest multicellular organisms collectively referred to as the "Gabonionta" ( ); y along western margin of Canadian Shield. *c.2,090 Ma – Eburnean Orogeny: Eglab Shield experiences syntectonic trondhjemitic pluton intrusion of its Chegga series – most of the intrusion is in the form of a plagioclase called oligoclase. *2.070 Ma – Eburnean Orogeny: asthenospheric upwelling releases large volume of post-orogenic magmas – magma events repeatedly reactivated from the Neoproterozoic to the Mesozoic. Orosirian Period *c.2,050 Ma – Period starts. Significant in most continents. *c.2,023 Ma – impact structure forms. *c.2,005 Ma – Glenburgh Orogeny (to c.1,920 Ma) begins: in western Australia begins to stabilize during period of substantial granite magmatism and deformation; Halfway Gneiss and Moogie Metamorphics result. Dalgaringa Supersuite (to c.1,985 Ma), comprising sheets, dykes and viens of mesocratic and leucocratic tonalite, stabilizes. *c.2,000 Ma – The lesser forms. The of produced by uranium-precipitant bacteria. First s. *c.1,900 - 1,880 Ma – biota forms flourishes including prokaryotes like , , and *c.1,850 Ma – . . First s. Bacterial viruses ( ) emerge before, or soon after, the divergence of the prokaryotic and eukaryotic lineages. *c.1,830 Ma – Capricorn Orogeny (1.83 - 1.78 Gyr) stabilizes central and northern Gascoyne Complex: formation of pelitic and psammitic schists known as Morrissey Metamorphics and depositing Pooranoo Metamorphics an amphibolite facies Statherian Period *c.1,800 Ma – Period starts. forms, one of whose fragments being . Oldest s develop on several cratons Barramundi Orogeny (ca. 1.8 Gyr) influences MacArthur Basin in Northern Australia. *c.1,780 Ma – (1.78 - 1.65 Gyr) influences southern margin of Wyoming craton - collision of Colorado orogen and Trans-Hudson orogen with stabilized Archean craton structure *c.1,770 Ma – (1.77 Gyr) influences southwest Montana: collision between Hearne and Wyoming cratons *c.1,765 Ma – As Kimban Orogeny in Australian continent slows, Yapungku Orogeny (1.765 Gyr) begins affecting Yilgarn craton in Western Australia - possible formation of , one of longest and most significant in Australia *c.1,760 Ma – Yavapai Orogeny (1.76 - 1.7 Gyr) impacts mid- to south-western United States *c.1,750 Ma – Gothian Orogeny (1.75 - 1.5 Gyr): formation of tonalitic-granodioritic plutonic rocks and calc-alkaline volcanites in the East European Craton *c.1,700 Ma – Stabilization of second major continental mass, the Guiana Shield in South America *c.1,680 Ma – Mangaroon Orogeny (1.68 - 1.62 Gyr), on the Gascoyne Complex in Western Australia: Durlacher Supersuite, granite intrusion featuring a northern (Minnie Creek) and southern belt - heavily sheared orthoclase porphyroclastic granites *c.1,650 Ma – Kararan Orogeny (1.65 Gyr) uplifts great mountains on the Gawler Craton in Southern Australia - formation of Gawler Range including picturesque Conical Hill Track and "Organ Pipes" waterfall Mesoproterozoic Era Calymmian Period *c.1,600 Ma – Mesoproterozoic Era and Period start. s expand. Major orogenic event in Australia: Isan Orogeny influences Mount Isa Block of Queensland - major deposits of lead, silver, copper and zinc are laid down. Mazatzal Orogeny (to c.1,300 Ma) influences mid- to south-western United States: Precambrian rocks of the , and , are formed establishing basement of Canyon with metamorphosed gneisses that are intruded by granites. in Montana/Idaho/BC formed in basin on edge of Laurentia. *c.1,500 Ma – Supercontinent Columbia splits apart: associated with continental rifting along western margin of Laurentia, eastern India, southern Baltica, southeastern Siberia, northwestern South Africa and North China Block - formation of Ghats Province in India. First structurally complex s (Hododyskia, colonial formamiferian?). Ectasian Period *c.1,400 Ma – Period starts. s expand. Major increase in diversity with widespread blue-green algae colonies and reefs dominating tidal zones of oceans and seas *c.1,300 Ma – Break-up of Columbia Supercontinent completed: widespread , forming anorthosite-mangerite-charnockite-granite suites in North America, Baltica, Amazonia and North China - stabilization of in South America (to c.1,000 Ma) in North America: globally associated with assembly of Supercontinent Rodinia establishes Grenville Province in Eastern North America - folded mountains from Newfoundland to North Carolina as Old Rag Mountain forms *c.1,270 Ma – Emplacement of Mackenzie granite mafic dike swarm - one of three dozen dike swarms, forms into Mackenzie Large Igneous Province - formation of Copper Creek deposits *c.1,250 Ma – Sveconorwegian Orogeny (to c.900 Ma) begins: essentially a reworking of previously formed crust on the Baltic Shield *c.1,240 Ma – Second major dike swarm, Sudbury dikes form in Northeastern Ontario around the area of the Sudbury Basin Stenian Period *c.1,200 Ma – Period starts. pubescens, earliest fossil evidence for ually reproducing . Meiosis and sexual reproduction are present in single-celled eukaryotes, and possibly in the common ancestor of all eukaryotes. Supercontinent of (1.2 Gyr - 750 Myr) completed: consisting of North American, East European, Amazonian, West African, Eastern Antarctica, Australia and China blocks, largest global system yet formed - surrounded by superocean Mirovia *c.1,100 Ma – First evolve: photosynthetic some develop mixotrophic habits ingesting prey - with their appearance, prey-predator relationship is established for first time forcing acritarchs to defensive strategies and leading to open "arms" race. Late Ruker (1.1 - 1 Gyr) and Nimrod Orogenies (1.1 Gyr) in Antarctica possibly begins: formation of mountain range and Vostok Subglacial Highlands. buckles in the south-central part of the North American plate - leaves behind thick layers of rock that are exposed in Wisconsin, Minnesota, Iowa and Nebraska and creates rift valley where future develops. *c.1,080 Ma – Musgrave Orogeny (ca. 1.080 Gyr) forms , an east-west trending belt of granulite-gneiss basement rocks - voluminous Kulgera Suite of granite and Birksgate Complex solidify *c.1,076 Ma – Musgrave Orogeny: Warakurna large igneous province develops - intrusion of Giles Complex and Winburn Suite of granites and deposition of Bentley Supergroup (including Tollu and Smoke Hill Volcanics) Neoproterozoic Era Tonian Period *c.1,000 Ma – Neoproterozoic Era and Period start. ends. First radiation of dinoflagellates and spiny s - increase in defensive systems indicate that acritarchs are responding to carnivorous habits of dinoflagellates - decline in stromatolite reef populations begins. starts to break up. First . Rayner Orogeny as proto-India and Antarctica collide (to c.900 Ma). Trace fossils of colonial Hododyskia (to c.900 Ma): possible divergence between animal and plant kingdoms begins. Stabilization of Satpura Province in Northern India. Rayner Orogeny (1 Gyr - 900 Myr) as India and Antarctica collide *c.920 Ma – Edmundian Orogeny (ca. 920 - 850 Myr) redefines Gascoyne Complex: consists of reactivation of earlier formed faults in the Gascoyne - folding and faulting of overlying Edmund and Collier basins *c.920 Ma – Adelaide Geosyncline laid down in central Australia - essentially a rift complex, consists of thick layer of sedimentary rock and minor volcanics deposited on Easter margin - limestones, shales and sandstones predominate *c.900 Ma – of Australia: in addition to prokaryote assemblage of fossils, cherts include eukaryotes with ghostly internal structures similar to green algae - first appearance of Glenobotrydion (900 - 720 Myr), among earliest plants on Earth *c.830 Ma – Rift develops on between continental masses of Australia, eastern Antarctica, India, Congo and Kalahari on one side and Laurentia, Baltica, Amazonia, West African and Rio de la Plata cratons on other - formation of Adamastor Ocean. *c.800 Ma – With free oxygen levels much higher, is disrupted and once again glaciation becomes severe - beginning of second "snowball Earth" event *c.750 Ma – First appears: as creatures like Paramecium, Amoeba and Melanocyrillium evolve, first animal-like cells become distinctive from plants - rise of herbivores (plant feeders) in the food chain. First Sponge-like animal: similar to early colonial foraminiferan Horodyskia, earliest ancestors of Sponges were colonial cells that circulated food sources using flagella to their gullet to be digested. glaciation (c.750 Ma): first major glaciation of Earth - almost entire planet is covered with ice sheets up to more than a kilometer thick and identified from units in Namibia and the South China Block Cryogenian Period *c.720 Ma – Period starts, during which Earth freezes over ( or ) at least 3 times, 720 Ma – continues process begun during Kaigas - great ice sheets cover most of the planet stunting evolutionary development of animal and plant life - survival based on small pockets of heat under the ice *c.700 Ma – Fossils of testate Amoeba first appear: first complex metazoans leave unconfirmed biomarkers - they introduce new complex body plan architecture which allows for development of complex internal and external structures. trail impressions in : because putative "burrows" under stromatolite mounds are of uneven width and tapering makes biological origin difficult to defend - structures imply simple feeding behaviours. Rifting of Rodinia is completed: formation of new superocean of as previous Mirovia ocean bed closes - Mozambique mobile belt develops as a suture between plates on Congo-Tanzania craton *c.660 Ma – As Sturtian glaciers retreat, (660 - 540 Myr) begins on north coast of : involving one or more collisions of island arcs on margin of future , terranes of , Armorica and are laid down *c.650 Ma – First appear: form first s of made from protein and silica - brightly coloured these colonial creatures filter feed since they lack nervous, digestive or circulatory systems and reproduce both sexually and asexually *c.650 Ma – Final period of worldwide glaciation, (650 - 635 Myr) begins: most significant "snowball Earth" event, global in scope and longer - evidence from deposits in South Australia laid down on Adelaide Geosyncline Ediacaran Period *c.635 Ma – period begins. End of Marinoan Glaciation: last major "snowball Earth" event as future ice ages will feature less overall ice coverage of the planet *c.633 Ma – Beardmore Orogeny (to c.620 Ma) in Antarctica: reflection of final break-up of Rodinia as pieces of the supercontinent begin moving together again to form Pannotia *c.620 Ma – Timanide Orogeny (to c.550 Ma) affects northern Baltic Shield: gneiss province divided into several north-south trending segments experiences numerous metasedimentary and metavolcanic deposits - last major orogenic event of Precambrian *c.600 Ma – begins: formed between plates separating supercontinent fragments Gondwana and - Supercontinent Pannotia (to c.500 Ma) completed, bordered by and Panthalassa oceans. Accumulation of atmospheric oxygen allows for the formation of : prior to this, land-based life would probably have required other chemicals to attenuate ultraviolet radiation enough to permit colonization of the land *c.575 Ma – First . *c.560 Ma – s, e.g., s, and small animals. Earliest s. Earliest . *c.558 Ma - a large slow moving disc-like creature appears - the discovery of fat molecules in its tissues make it the first confirmed true metazoan animal of the fossil record. *c.555 Ma – The first possible mollusk appears. *c.550 Ma – First possible comb-jellies, sponges, corals, and anemones. *c.550 Ma - or Ayres Rock begins forming during the in Australia *c.544 Ma – The first appears. Phanerozoic Eon Paleozoic Era Cambrian Period *c. Ma – beginning of the Period, the and the current Eon. End of the Ediacaran Period, the Eon and the Supereon. The disappears, while the initiates the emergence of most forms of complex life, including s ( ), s, s and . breaks up into several smaller continents: , and . *c.540 Ma – Supercontinent of breaks up. *c.530 Ma – First - appearance of *c.525 Ma – First s. *c. Ma – First s *c. 518 Ma - flourishes - Maotianshan Shales reveal numerous invertebrates and arthropods that appear in the Burgess shales suggesting their range is global and includes a number of chordates including , and early fish like . *c.514 Ma - trilobites appear, the largest members of the Cambrian Trilobites *c.505 Ma – Deposition of the - Biota includes numerous strange invertebrates and arthropods like ; First great apex predator dominates. *c.490 Ma - Beginning of the as three continents and terranes of Laurentia, Baltica and Avalonia collide resulting in mountain-building recorded in the northern parts of Ireland and Britain, the , , eastern Greenland and parts of north-central Europe. Ordovician Period *c. Ma – Beginning of the and the end of the Period. *c.485 Ma – First jawless fish - radiation of fish into the Silurian *c.450 Ma - Late Ordovician microfossils of scales indicate the earliest evidence for the existence of jawed fish or . *c.450 Ma – and s colonize the land. s evolve. Silurian Period *c. Ma – Beginning of the and the end of the Period. *c.433 Ma - Fault begins shaping the as the Caledonian Orogeny reaches its close. *c.430 Ma - First appearance of the oldest known plant to have a stem with and is thus a between the primitive non-vascular and the *c.420 Ma – First creature took a . First ray-finned fish and land scorpions. *c.410 Ma – First toothed fish and s. Devonian Period *c. Ma – Beginning of the and end of the Period. First s. *c.419 Ma - sediments begin being laid in the North Atlantic region including, Britain, Ireland, Norway and in the west along the northeastern seaboard of North America. It also extends northwards into Greenland and Svalbard. *c. 415 Ma - , an iconic member of the , appears, the most advanced of the jawless fish. Its boney armor serves as protection agains the successful radiation of and as a way to live in calcium-poor fresh water environments. *c.395 Ma – First of many modern groups, including s. *c.375 Ma - begins influencing mountain building along the Atlantic seaboard of North America. *c.370 Ma - an early shark appears. *c.360 Ma – First s and s. *c.350 Ma – First large sharks, and . Carboniferous Period *c. Ma – Beginning of the and the end of . s diversify. *c.345 Ma - a representative of the appears as part of a successful radiation of the echinoderms. *c.330 Ma – First s evolve. *c.320 Ma – First s evolve. *c.315 Ma – The evolution of the first . *c.312 Ma - makes first appearance, one of the oldest reptiles found in the fossil record. *c.306 Ma - evolves in the swamps with an unusual boomerang-like skull. *c.305 Ma – First s evolve; a giant dragonfly dominates the skies. *c.300 Ma - Last great period of mountain building episodes in Europe and North America in response to the final suturing together of the supercontinent - the are uplifted Permian Period *c. Ma – End of and beginning of Permian Period. By this time, all continents have fused into the of . s evolve. s and s diversify along with s and s. *c.275 Ma – First s evolve. *c.251.4 Ma – . End of Period and of the Era. Beginning of Period, the and of the age of the dinosaurs. Mesozoic Era Triassic Period *c. Ma – and begin. begins. *c.245 Ma – First s. *c.240 Ma – s and s diversify. *c.225 Ma – First s and evolve. *c.220 Ma – First ns and . *c.215 Ma – First s. Long-necked dinosaurs and , one of the earliest dinosaurs, evolve. First s. Jurassic Period *c. Ma – marks the end of Triassic and beginning of Period. The largest dinosaurs, such as and evolve during this time, as do the ; large, bipedal predatory dinosaurs such as . First specialized s and s. s diversify. *c.190 Ma – s evolve, along with many groups of primitive sea invertebrates. *c.180 Ma – splits into two major continents: in the north and in the south. *c.176 Ma – First s. *c.170 Ma – First s and s evolve. s go extinct. *c.165 Ma – First s. *c.161 Ma – First s. *c.155 Ma – First s and s. s and s diversify. Cretaceous Period *c. Ma – End of and beginning of Period. *c.130 Ma – and begin to split apart as the forms. First s. *c.115 Ma – First s. *c.110 Ma – First . *c.106 Ma – evolves. *c.100 Ma – First s. *c.90 Ma – the splits from , becoming an island . s go extinct. s and s evolve. *c.80 Ma – Australia splits from . First s. *c.70 Ma – s diversify. *c.68 Ma – evolves. *c. .038 ± 0.011 Ma – at the end of the Period marks the end of the era and the age of the ; start of the Period and the current era. Cenozoic Era Paleogene Period *c.63 Ma – First s. *c.60 Ma – Evolution of the first and s. Flightless birds diversify. *c.56 Ma – evolves. *c.55 Ma – the island of the collides with Asia, thrusting up the and the . Many modern bird groups appear. First ancestors. First s, s, s, s, s, s, s, and s. s diversify. *c.52 Ma – First s. *c.50 Ma – Africa collides with , closing the . Divergence of and ancestors. diversify. s, s, s, and s evolve. *c.49 Ma – s return to the water. * c.45 Ma - s evolve in North America. *c.40 Ma – Age of the parvorder; first evolve. n insects become recognizable. goes extinct. evolves. *c.37 Ma – First s. *c. Ma – End of , start of epoch. *c.35 Ma – s first appear. s, s, peccaries, dogs, eagles, and hawks evolve. *c.33 Ma – First marsupials evolve. *c.30 Ma – s go extinct. Pigs evolve. separates from Antarctica, becoming an island continent. *c.28 Ma – evolves. *c.26 Ma – Emergence of the first true . *c.25 Ma – First deer. s . Neogene Period *c. Ma – Period and epoch begin *c.20 Ma – Giraffes and s evolve. *c.18-12 Ma – estimated age of the /'' '' (great apes vs. gibbons) split. *c.15 Ma – First s, s, and kangaroos. Australian megafauna diversify. *c.10 Ma – Insects diversify. First large horses. Camels cross from America to Asia. *c.6.5 Ma – First members of the tribe. *c.6 Ma – s diversify. *c.5.96 Ma – - 5.33 Ma – : the precursor of the current closes repeatedly, leading to a partial desiccation and strong increase in salinity of the . *c.5.4-6.3 Ma – Estimated age of the / (human vs. chimpanzee) . *c.5.5 Ma – Appearance of the genus *c.5.33 Ma – : the Strait of Gibraltar opens for the last (and current) time and water from the Atlantic Sea fills again the Mediterranean Sea basin. *c. Ma – epoch begins. First tree sloths and hippopotami. First large vultures. s go extinct. *c.4.8 Ma – The appears. *c.4.5 Ma – appearance of the genus *c.3 Ma – joins North and South America. . s, s, s and s move south; s, s, and s move north. *c.2.7 Ma – evolve. *c.2.6 Ma – current begins Quaternary Period *c. Ma – start of the epoch, the and the current Period; emergence of the genus . , the best known of the s, appears. *c.1.9 Ma – Oldest known fossils. This species might be evolved some time before, up to c.2 Ma ago. *c.1.7 Ma – s go extinct. *c.1.8-0.8 Ma – by . *c.1.5 Ma – earliest possible evidence of the controlled use of by *c.1.2 Ma – evolves. dies out. *c.0.79 Ma – earliest demonstrable evidence of the controlled use of by *c.0.7 Ma – last reversal of the *c.0.7 Ma: oldest archaic hominins that broke away from the modern human lineage that were found to have inserted into the Sub-Saharan African population genome approximately 35,000 years ago. *c.0.64 Ma – erupts *c.0.6 Ma – evolves. *c.0.315 Ma – begins. Appearance of in Etymology of period names References Category:Timeline